<template>
  <div class="goods-sku">
    <dl v-for="item in goods.specs" :key="item.id">
      <dt>{{ item.name }}</dt>
      <dd>
        <template v-for="val in item.values" :key="val.name">
          <img
            :class="{ selected: val.selected, disabled: val.disabled }"
            @click="clickSpecs(item, val)"
            v-if="val.picture"
            :src="val.picture"
          />
          <span
            :class="{ selected: val.selected, disabled: val.disabled }"
            @click="clickSpecs(item, val)"
            v-else
            >{{ val.name }}</span
          >
        </template>
      </dd>
    </dl>
  </div>
</template>
<script>
import { watchEffect } from "vue";
import getPowerSet from "./power-set";
const spliter = "★";
// 根据skus数据得到路径字典对象
const getPathMap = (skus) => {
  const pathMap = {};
  if (skus && skus.length > 0) {
    skus.forEach((sku) => {
      // 1. 过滤出有库存有效的sku
      if (sku.inventory) {
        // 2. 得到sku属性值数组
        const specs = sku.specs.map((spec) => spec.valueName);
        // 3. 得到sku属性值数组的子集
        const powerSet = getPowerSet(specs);
        // 4. 设置给路径字典对象
        powerSet.forEach((set) => {
          const key = set.join(spliter);
          // 如果没有就先初始化一个空数组
          if (!pathMap[key]) {
            pathMap[key] = [];
          }
          pathMap[key].push(sku.id);
        });
      }
    });
  }
  return pathMap;
};

// 初始化禁用状态
function initDisabledStatus(specs, pathMap) {
  if (specs && specs.length > 0) {
    specs.forEach((spec) => {
      spec.values.forEach((val) => {
        // 设置禁用状态
        val.disabled = !pathMap[val.name];
      });
    });
  }
}

// 得到当前选中规格集合
const getSelectedArr = (specs) => {
  const selectedArr = [];
  specs.forEach((spec, index) => {
    const selectedVal = spec.values.find((val) => val.selected);
    if (selectedVal) {
      selectedArr[index] = selectedVal.name;
    } else {
      selectedArr[index] = undefined;
    }
  });
  return selectedArr;
};

// 更新按钮的禁用状态
const updateDisabledStatus = (specs, pathMap) => {
  // 遍历每一种规格
  specs.forEach((item, i) => {
    // 拿到当前选择的项目
    const selectedArr = getSelectedArr(specs);
    // 遍历每一个按钮
    item.values.forEach((val) => {
      if (!val.selected) {
        selectedArr[i] = val.name;
        // 去掉undefined之后组合成key
        const key = selectedArr.filter((value) => value).join(spliter);
        val.disabled = !pathMap[key];
      }
    });
  });
};

export default {
  name: "XtxGoodSku",
  props: {
    // specs:所有的规格信息  skus:所有的sku组合
    goods: {
      type: Object,
      default: () => ({ specs: [], skus: [] }),
    },
  },
  emits: ["change"],
  setup(props, { emit }) {
    let pathMap = {};
    watchEffect(() => {
      // 得到所有字典集合
      pathMap = getPathMap(props.goods.skus);
      // 组件初始化的时候更新禁用状态
      initDisabledStatus(props.goods.specs, pathMap);
    });

    const clickSpecs = (item, val) => {
      if (val.disabled) return false;
      // 选中与取消选中逻辑
      if (val.selected) {
        val.selected = false;
      } else {
        item.values.forEach((bv) => {
          bv.selected = false;
        });
        val.selected = true;
      }
      // 点击之后再次更新选中状态
      updateDisabledStatus(props.goods.specs, pathMap);
      // 把选择的sku信息传出去给父组件
      // 触发change事件将sku数据传递出去
      const selectedArr = getSelectedArr(props.goods.specs).filter(
        (value) => value
      );
      // 如果选中得规格数量和传入得规格总数相等则传出完整信息(都选择了)
      // 否则传出空对象
      if (selectedArr.length === props.goods.specs.length) {
        // 从路径字典中得到skuId
        const skuId = pathMap[selectedArr.join(spliter)][0];
        const sku = props.goods.skus.find((sku) => sku.id === skuId);
        // 传递数据给父组件
        emit("change", {
          skuId: sku.id,
          price: sku.price,
          oldPrice: sku.oldPrice,
          inventory: sku.inventory,
          specsText: sku.specs
            .reduce((p, n) => `${p} ${n.name}：${n.valueName}`, "")
            .trim(),
        });
      } else {
        emit("change", {});
      }
    };
    return { clickSpecs };
  },
};
</script>

<style scoped lang="scss">
@mixin sku-state-mixin {
  border: 1px solid #e4e4e4;
  margin-right: 10px;
  cursor: pointer;

  &.selected {
    border-color: green;
  }

  &.disabled {
    opacity: 0.6;
    border-style: dashed;
    cursor: not-allowed;
  }
}

.goods-sku {
  padding-left: 10px;
  padding-top: 20px;

  dl {
    display: flex;
    padding-bottom: 20px;
    align-items: center;

    dt {
      width: 50px;
      color: #999;
    }

    dd {
      flex: 1;
      color: #666;

      > img {
        width: 50px;
        height: 50px;
        margin-bottom: 4px;
        @include sku-state-mixin;
      }

      > span {
        display: inline-block;
        height: 30px;
        line-height: 28px;
        padding: 0 20px;
        margin-bottom: 4px;
        @include sku-state-mixin;
      }
    }
  }
}
</style>